The joint meeting of conferences focused on Cellular Immunity and Immunotherapy in Cancer and Molecular Immunology of Virus Infections will enable cross-discipline interactions between two emerging and interrelated but distinct fields. Recent advances in the understanding of the biochemistry and cell biology of antigen processing and presentation, structural interactions between antigens and products of the immune system, definition of B and T cell epitopes, along with development and refinement of animal models to study immunity, have made it possible to address questions regarding immune responses to specific challenges to the integrity of the organism. Two such challenges are viral infections and malignancies. The proposed meetings include two joint addresses at the start and completion of the meeting; Rolf Zinkernagel will outline the essential issues at the beginning of the week, and Phil Leder will sum the critical understandings at the conclusion of the meeting. In addition throughout the meeting, there will be three shared symposia focussing on a) the cell biology of antigen processing and presentation (Drs. Townsend, Braciale, Reiss and Cresswell), b) immune suppression and anergy (Drs. Jenkins, Ahmed, Groopman, Mosman, Nelson, and Allison), and c) vaccine design and strategies (Drs. Berzofsky, Rammensee, Liew, Lewis, and Bloom). By bringing together viral and tumor immunologists and immunotherapists under the auspices of parallel meeting with joint sessions of mutual interest, the newest immunological concepts, problems, and potential solutions developed in these two systems will be evaluated in an atmosphere of intense and collegial scientific exchange.